[LLVMdev] insert nop instruction (original) (raw)

Zahra Marj zahrafatehimarj at gmail.com
Thu Jul 9 04:33:29 PDT 2015

My pass runs after optimization passes.

On Thu, Jul 9, 2015 at 1:11 PM, David Chisnall <David.Chisnall at cl.cam.ac.uk> wrote:

Hi,

What are you trying to achieve? Inserting NOPs into LLVM IR is likely to be pointless, as optimisations (in the IR or SelectionDAG) will remove them before machine code generation. If you want to insert NOPs into the generated machine code, then this will not help you (you could insert inline assembly containing nops into the IR). David > On 9 Jul 2015, at 09:25, Zahra Marj <zahrafatehimarj at gmail.com> wrote: > > Hi. > I need to write a function pass that insert nop instruction in function. Examples of these instructions are: %nop = add i1 0, 0 or %nop = alloca i1, i1 0. This link couldn't help me: http://llvm.org/docs/ProgrammersManual.html#creating-and-inserting-new-instructions > I need a clear example about inserting new instruction. Anyone can help me? > Thanks. _> ________________________ > LLVM Developers mailing list > LLVMdev at cs.uiuc.edu http://llvm.cs.uiuc.edu > http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20150709/19bca1c9/attachment.html>

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